1. Field of the Invention
The present invention relates to a reserve device for optical fibers, each optical fiber being protected by at least one tubular duct, said device being formed of a case having a flat bottom and a lid, said bottom being provided with a core defining a recess having substantially the form of a closed loop omega, at the ends of which are provided an inlet channel and an outlet channel for the optical fibers.
The present invention relates then to cases for storing optical fibers and more particularly to cassettes intended to receive bundles of optical fibers at their exit from optical cables, so as to protect the fibers and to provide reserve lengths in the path of the bundle.
The purpose of these cassettes is essentially to provide an optical fiber reserve at the ends of the optical fibers, while providing mechanical protection, so as to protect the fibers and not to affect their transmission characteristics and their lifespan while respecting their minimum radius of curvature.
These cassettes find their application in optical fiber telecommunications lines, in teledistribution video communication networks for example.
2. Description of the Prior Art
From the French application No. 2 566 756 a reserve device of the above type is already known. In this device, each of the optical fibers being disposed in one tubular protection duct, it is coiled, around the core, provided with its protection duct.
From the article "Optical Fiber Patchcord Tensile Protector" in Research Disclosure No. 186, October 1979, pages 555-556, No. 18 637, Industrial Opportunities limited, Havant, Hants. G. B. a device is known of a closely related type in which one protection duct is provided of a diameter substantially wider than the diameter of the fiber, this latter being coiled while remaining provided with its protection duct.
From the French patent No. 2 573 877, in the name of the applicant, a device of a closely related type is also known in which the fibers are stored in flexible tubular ducts, each tubular duct being a thick ribbon preventing overlapping of the turns.
Now, these prior art devices are not satisfactory under conditions where high temperature variations occur. In fact, since the tubular ducts are generally made from a synthetic material, they do not have the same coefficient of elasticity, during temperature variations, as the optical fibers, which generally leads to breakages or voltages harmful for the optical fibers.
The invention proposes overcoming these defects of the prior art cassettes.